• 디지털융복합연구
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• 제15권8호
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• pp.195-202
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• 2017

Unmanned Aerial Vehicle (UAV)는 군사적 목적으로 주로 이용되었지만 ICT의 발전과 저렴해진 제작비용으로 인해 다양한 민간 서비스에서도 점차 이용되고 있다. UAV는 앞으로 스스로 임무를 수행하는 자율비행을 할 것이라 기대되고 있는데, 복잡한 임무를 수행하기 위해서는 군집 비행이 필수적이다. UAV 군집 비행은 기존 UAV 시스템과 네트워크 및 인프라 구조가 달라 국내외에서 많은 연구가 이루어지고 있지만, 아직 안전한 UAV 군집 비행을 위한 보안위협 및 보안요구사항에 대한 연구가 이루어지지 않고 있다. 본 논문에서는 이러한 문제점을 해결하기 위하여 UAV 자율비행기술을 미 공군 연구소와 미국 육군 공병대를 기반으로 정의하고 UAV 군집비행기술 및 보안위협을 분류하였다. 그리고 각 UAV 군집비행기술의 보안위협에 따른 보안요구사항을 정의하여 비교 분석함으로써 향후 안전한 UAC 자율비행 기술 발전에 기여할 수 있도록 하였다.

• 한국운동역학회지
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• 제23권4호
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• pp.369-376
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• 2013

The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.

• 한국식품조리과학회지
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• 제29권6호
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• pp.709-715
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• 2013

The purposes of this study were to consider the influence of person-environment fit in the family restaurants on employees' stress. Based on total 274 samples obtained from empirical research from March 20 to April 10, 2013, self-administrated questionnaires were completed by patrons in metropolitan area and data were analysed by frequency, exploratory factor analysis, reliability analysis, correlation analysis, t-test, one-way ANOVA, and multi-regression analysis. Results of study were as follows: From the exploratory factor analysis of the variables, 4 factors, i.e. person-organization fit(3 variables), person-job fit(3 variables), person-supervisor fit(3 variables), and employees' stress(5 variables) were extracted. The results showed that employees' person-organization fit was significant differences according to gender(male $4.43{\pm}1.45$; female $4.83{\pm}1.34$; p<0.05). In terms of employees' person-supervisor fit was significant differences according to age(20' $3.08{\pm}0.99$, 30' $3.52{\pm}0.10$; 40' $3.71{\pm}1.07$; p<0.05). Also, the person-job fit(${\beta}$=-0.472; p<0.001), and person-supervisor fit(${\beta}$=-0.285; p<0.001) among the person-environment fit had a significant negative effect on employees' stress. Limitations and future research directions are also discussed.

• 한국주거학회논문집
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• 제25권3호
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• pp.25-34
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• 2014

The major purposes of this study were to analyze main features of US Green Building Council's LEED for Homes rating system and examine residents' satisfaction on their LEED-certified homes and neighborhoods. The first part of this article shows the structure and features of the LEED for Homes rating system and the process to obtain credits of this rating system. The investigation to assess residents' satisfaction targeted LEED certified home residents in Midwest in the United State. The satisfaction was assessed in relation to socio-demographic and housing characteristics. To collect data, a quantitative survey was administered to the residents of LEED-certified homes in Midwest in the US. A total of 605 surveys was sent out and 235 were collected, yielding a 38.8% response rate. Findings revealed that LEED-certified home residents were highly satisfied with their homes and neighborhood although neighborhood satisfaction was lower than housing satisfaction. Residents' income and education were the significant socio-demographic factors that show significant relationships with housing satisfaction. Residents' home ownership, length of residence, housing types were significant housing characteristics on their satisfaction while the levels of LEED certifications (i.e., certified, silver, gold, and platinum) were not significantly related to housing satisfaction. The findings of this study suggest the importance of developing effective strategies for those who are less educated, lower income classes, renters, or multi-attached housing residents for more successful development of LEED-certified homes in the future.

• Earthquakes and Structures
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• 제18권1호
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• pp.27-44
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• 2020

This work presents a comparison of three performance-based seismic design methods (PBSD) as applied to plane steel frames having eccentric braces (EBFs) and buckling restrained braces (BRBFs). The first method uses equivalent modal damping ratios (ξ_k), referring to an equivalent multi-degree-of-freedom (MDOF) linear system, which retains the mass, the elastic stiffness and responds in the same way as the original non-linear MDOF system. The second method employs modal strength reduction factors (${\bar{q}}_k$) resulting from the corresponding modal damping ratios. Contrary to the behavior factors of code based design methods, both ξ_k and ${\bar{q}}_k$ account for the first few modes of significance and incorporate target deformation metrics like inter-storey drift ratio (IDR) and local ductility as well as structural characteristics like structural natural period, and soil types. Explicit empirical expressions of ξ_k and ${\bar{q}}_k$, recently presented by the present authors elsewhere, are also provided here for reasons of completeness and easy reference. The third method, developed here by the authors, is based on a hybrid force/displacement (HFD) seismic design scheme, since it combines the force-base design (FBD) method with the displacement-based design (DBD) method. According to this method, seismic design is accomplished by using a behavior factor (q_h), empirically expressed in terms of the global ductility of the frame, which takes into account both non-structural and structural deformation metrics. These expressions for q_h are obtained through extensive parametric studies involving non-linear dynamic analysis (NLDA) of 98 frames, subjected to 100 far-fault ground motions that correspond to four soil types of Eurocode 8. Furthermore, these factors can be used in conjunction with an elastic acceleration design spectrum for seismic design purposes. Finally, a comparison among the above three seismic design methods and the Eurocode 8 method is conducted with the aid of non-linear dynamic analyses via representative numerical examples, involving plane steel EBFs and BRBFs.

• Steel and Composite Structures
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• 제26권6호
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• pp.745-757
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• 2018

The inclusion of a ductile steel bracing as means of repairing an earthquake-damaged bridge bent is evaluated and experimentally assessed for the purposes of restoring the damaged bent's strength and stiffness and further improving the energy dissipation capacity. The study is focused on substandard reinforced concrete multi-column bridge bents constructed in the 1950 to mid-1970 in the United States. These types of bents have numerous deficiencies making them susceptible to seismic damage. Large-scale experiments were used on a two-column reinforced concrete bent to impose considerable damage of the bent through increasing amplitude cyclic deformations. The damaged bent was then repaired by installing a ductile fuse steel brace in the form of a buckling-restrained brace in a diagonal configuration between the columns and using post-tensioned rods to strengthen the cap beam. The brace was secured to the bent using steel gusset plate brackets and post-installed adhesive anchors. The repaired bent was then subjected to increasing amplitude cyclic deformations to reassess the bent performance. A subassemblage test of a nominally identical steel brace was also conducted in an effort to quantify and isolate the ductile fuse behavior. The experimental data from these large-scale experiments were analyzed in terms of the hysteretic response, observed damage, internal member loads, as well as the overall stiffness and energy dissipation characteristics. The results of this study demonstrated the effectiveness of utilizing ductile steel bracing for restoring the bent and preventing further damage to the columns and cap beams while also improving the stiffness and energy dissipation characteristics.

• 드라이브 ㆍ 컨트롤
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• 제14권2호
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• pp.30-36
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• 2017

This paper presents a sliding mode observer-based fault detection algorithm for steering inputs of an all-terrain crane. All-terrain cranes with multi-axles have several steering modes for various working purposes. Since steering angles at the other axles except the first wheel are controlled by using the information of steering angle at the first wheel, a reliable signal of the first axle's steering angle should be secured for the driving safety of cranes. For the fault detection of steering input signal, a simplified crane model-based sliding mode observer has been used. Using a sliding mode observer with an equivalent output injection signal that represents an actual fault signal, a fault signal in steering input was reconstructed. The road steering mode of the crane's steering system was used to conduct performance evaluations of a proposed algorithm, and an arbitrary fault signal was applied to the steering angle at the first wheel. Since the road steering mode has different steering strategies according to different speed intervals, performance evaluations were conducted based on the curved path scenario with various speed conditions. The design of algorithms and performance evaluations were conducted on Matlab/Simulink environment, and evaluation results reveal that the proposed algorithm is capable of detecting and reconstructing a fault signal reasonably well.

• 한국농촌건축학회논문집
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• 제6권2호
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• pp.1-10
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• 2004

The purpose of this study is to clarify the actual condition of the layout and floor planning of elementary schools for the 7th education curriculum. This article discuses about the basic characteristics of the plan composition and the outdoor spaces of 35 elementary schools in Gyeongnam prefecture. The results of this study are summarized as follows; 1) To respond to the 7th educational curriculum, unit classrooms need to be expanded or space for a multi-purpose room needs to be secured to serve the following purposes: the operation of educational program by the level and offering of unified Subjects. overall, elementary schools need to seek ways to deal with problems associated with space composition, types of classrooms, and changes in the number of classrooms so that the 7th Educational curriculum can be carried out smoothly. 2) Different from the past, various plan types are available nowadays. Even in case of schools with the same class size, their areas were different by 130 percentages or higher. Therefore, practicality needs to be more focused than facility standards in order for the school to cope with changes in future educational environment. 3) When designing the elementary school in the future, more space needs to be assigned for learning by expanding facilities - special purpose classrooms and supporting facilities - to accommodate students' various learning activities. In addition, faculty facilities need to be rearranged to promote research and development as well as to ensure the operation of the educational program. And, resident facilities that consider the close connection with the local community need to be rearranged in an efficient manner as well.

• 한국실내디자인학회논문집
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• 제22권5호
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• pp.284-292
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• 2013

The study performed analysis focusing on specialized convention and exhibition facilities among convention and exhibition facilities in Korea. The procedures and results were as follows: First, by theoretical consideration, meaning and contents of convention and exhibition programs done in convention and exhibition facilities were considered and after that, general characteristics of the programs which were the main of space utilization was derived. Second, considering scale and location, 6 facilities were re-selected for in-depth research from 12 facilities investigated preliminarily. Selected facilities were categorized by scale and through the analysis of programs done in this facilities for the last 1 year, overview and characteristics of utilization for exhibition space, conference space, and multi-purpose space, etc were analyzed. Third, through the case study on the programs, individual characteristics of space utilization by convention and exhibition program were analyzed. From the result of the study, considering the whole, the space utilization of programs was done as conference space rather than exhibition space and the ratio of use as conference space to use as exhibition space was 1.8 in the large facilities, 6.7 and 7.6 in the middle facilities and the small facilities, respectively. In the middle and small facilities, the ratio of use of one room as conference space was very high. In the large facilities, there was no big difference with the ratio 50:50 of the programs involving exhibition to other programs, but in the middle and small facilities, the ratio of the former to the latter was observed over 2.4 and 3.6. This fact indicated that the function of use as promotion and communication space for companies and industrial entities which were the essential purposes became low.

• 정보관리학회지
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• 제25권3호
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• pp.65-82
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• 2008

검색 자원의 증가와 멀티 버전 자료의 증대에 따라 목록의 기능 중 집중기능이 필요하게 되면서, FRBR(Functional Requirements for Bibliographic Records)이 제안되었으나, 기존 서지데이터를 FRBR로 변환시 불완전함과 FRBR을 구체화할 목록규칙의 부재 등 현행 목록데이터를 FRBR로 완벽히 구현하기에는 한계가 있다. FRBR을 온라인목록에 적용하기 위해서는 방대한 양의 기존 MARC 데이터를 FRBR 알고리즘으로 처리해야 하지만, 기입력된 MARC 데이터와 현행 목록규칙은 FRBR을 완벽히 지원하지 않기 때문에 FRBR로의 변환이 용이하지 않다. 따라서 목록규칙과 MARC 기술에 대한 지침이 필요하다. 또한 국내에 FRBR 시스템을 구축하기 위해서는 FRBR 알고리즘을 실재 목록시스템에 적용하여 문제점과 해결책을 모색해야 한다. 이에 본고는 FRBR을 목록에 적용하기 위해서는 FRBR을 위한 목록규칙과 MARC 데이터 기술 방안이 선행되어야 한다는 전제하에 FRBR을 위한 저작 표현형 알고리즘을 개발하고, 실재 도서관 시스템에 적용하여 저작의 집중도와 적용시의 문제점을 분석하고, FRBR의 저작 집중성을 높이기 위한 방안으로 목록규칙과 MARC 입력방안을 제안하고 이를 검증하였다.